Certain Thyroid-Related Diseases May Vary by Race
Study looked at Graves', Hashimoto's thyroiditis among U.S. military personnel
By Dennis Thompson
TUESDAY, April 15, 2014 (HealthDay News) -- Race appears to be a factor in determining a person's risk of developing autoimmune thyroid conditions such as Graves' disease or Hashimoto's thyroiditis, a new study says.
African Americans and Asians are much more likely to develop Graves' disease than whites are, according to the study published in the April 16 issue of the Journal of the American Medical Association.
On the other hand, whites have an increased risk of Hashimoto's thyroiditis when compared to other ethnic groups, the researchers found.
The findings are based on analysis of medical records from all United States active duty military personnel aged 20 to 54 from 1997 through 2011.
"These stark race differences in the incidence of autoimmune thyroid disease raise the important question of why?" said lead author Donald McLeod, an endocrinologist and researcher at the QIMR Berghofer Medical Research Institute in Queensland, Australia. "If we can work this out, we may unlock the mechanisms of autoimmune thyroid disease, and potentially yield insights into other autoimmune disorders."
The thyroid gland plays a crucial role in regulating the body's metabolism, influencing how quickly a person burns calories, how fast their heart beats, and how alert they feel.
Graves' disease occurs when the immune system begins producing an antibody that tricks the thyroid into producing too much hormone. It's the most common cause of hyperthyroidism, and affects about one in every 200 people, according to the U.S. National Institutes of Health (NIH).
Hashimoto's thyroiditis happens when the immune system attacks the thyroid gland itself, causing hormone production to fall and causing hypothyroidism. Hashimoto's affects as many as 5 percent of adults, according to the NIH.
Both conditions are chronic illnesses but can be treated with medication. Left untreated, people with Graves'-related hyperthyroidism can become nervous or irritable and suffer hand tremors, a rapid and irregular heartbeat, and weight loss. Hypothyroidism caused by Hashimoto's has almost the opposite effect on the body, causing people to experience fatigue, difficulty concentrating, a slowed heart rate and mild weight gain.
The analysis found that, compared to whites, black women are about twice as likely and black men are about two and a half times more likely to have Graves' disease.
Asian/Pacific Islander women had a 78 percent increased risk of Graves' disease compared to whites, while Asian/Pacific Islander men had a more than threefold increased risk, the study noted.
But the risk of Hashimoto's in both blacks and Asian/Pacific Islanders was much lower than the risk among whites, ranging from 67 percent to 78 percent less, the findings showed.
"The findings are striking, that there are so many more African Americans and Asian individuals who are coded as having Graves'," said Dr. James Hennessey, director of clinical endocrinology at Beth Israel Deaconess Medical Center in Boston. He was not involved with the new research.